---
title: Tag Management
description: Learn how tag management is implemented as a non-rendered WKWebView instance to execute the Universal Tag (utag.js) JavaScript client-side.
url: https://docs.tealium.com/platforms/ios-objective-c/tag-management/
---
This tag management feature lets you integrate JavaScript based vendor tags into your app and manage them remotely using Tealium iQ, similarly to a website.
## How It Works
Once you have [created a mobile profile in Tealium iQ](https://docs.tealium.com/creating-a-mobile-profile/) with Tag Management enabled, when you initialize the Tealium instance in your app, a non-rendered web view is created to load a simple HTML file from Tealium in which to load the Universal Tag `utag.js`. This web view is never rendered to the user.
* Versions 5.5.0 and newer, running iOS 11.0 and newer use [WKWebView](https://developer.apple.com/documentation/webkit/wkwebview?language=objc).
* Versions 5.4.x and older, running iOS 10.0 and older use [UIWebView](https://developer.apple.com/documentation/uikit/uiwebview).
If you are supporting iOS versions lower than iOS 11.0 and would still like to use WKWebView, then upgrade to version 5.5.0 or newer. The caveat is that your visitor_id and other cookies will be reset. This is because the [WKHTTPCookieStore](https://developer.apple.com/documentation/webkit/wkhttpcookiestore) is only supported in iOS 11.0
### Sample
To better familiarize yourself with Tealium's `WKWebView`, explore the [WKWebView sample](https://github.com/Tealium/tealium-ios/tree/master/Samples/iOS_WKWebView%2BTealium_Objc).
### Usage
`WKWebView` is required to be attached to a `UIView`, even if it is not rendered. To accommodate this the Tealium SDK attempts to attach the non-rendered `WKWebView` to the `rootViewController.view`, the most common scenario when your window's `rootViewController` is a subclass of `UIViewController` or one of Apple's container view controllers (`UINavigationController` or `UITabBarController`).
If your app has a complex view hierarchy, set the `TEALConfiguration` instance with a view to attach to in `viewDidLoad`, `viewWillAppear:`, or `viewDidAppear:`.
```obj-c
TEALConfiguration *tealConfig = [TEALConfiguration configurationWithAccount:@"ACCOUNT"
profile:@"PROFILE"
environment:@"ENVIRONMENT"
datasource:@"DATASOURCE"];
tealConfig.view = ; // For example, self.view in a UIViewController subclass
// Initialize with a unique key for this instance
Tealium *tealium = [Tealium newInstanceForKey:@"INSTANCE" configuration:tealConfig];
```
| Parameters | Type | Description | Example |
|:--------------|:---------|:---------------------------------------------------|:---------------|
| `account` | `String` | Tealium account name | `"companyXYZ"` |
| `profile` | `String` | Tealium profile name | `"main" ` |
| `environment` | `String` | Tealium environment name | `"prod"` |
| `datasource` | `String` | (Optional) data source key (Set to `null` if none) | `"abc123"` |
Upon receiving a push notification, if your app jumps to a `UIViewController` and has a different view hierarchy than when Tealium was initialized, you must remove the old instance of Tealium and create a new one with the view to attach to. The sample app shows an example of this in [`GreenViewController.m`](https://github.com/Tealium/tealium-ios/blob/master/Samples/iOS_WKWebView%2BTealium_Objc/iOS_WKWebView%2BTealium_Objc/GreenViewController.m) and [TealiumHelper.m](https://github.com/Tealium/tealium-ios/blob/master/Samples/iOS_WKWebView%2BTealium_Objc/iOS_WKWebView%2BTealium_Objc/TealiumHelper.m).
Although the Objective-C SDK is currently closed source, to provide more context, this following code snippet shows how the web view is created.
```obj-c
- (UIView *_Nullable)webViewContainer {
if (!_webViewContainer) {
UIWindow *window = [[UIApplication sharedApplication] keyWindow];
UIViewController *rootViewController = window.rootViewController;
UIViewController *topViewController;
if ([rootViewController isKindOfClass:[UINavigationController class]]) {
topViewController = [((UINavigationController *)rootViewController).viewControllers lastObject];
} else if ([rootViewController isKindOfClass:[UITabBarController class]]) {
topViewController = ((UITabBarController *)rootViewController).selectedViewController;
} else {
topViewController = rootViewController;
}
UIView *view = topViewController.viewIfLoaded;
if (view) {
self.webViewContainer = view;
}
}
return _webViewContainer;
}
```
The view is only used once to initialize the `WKWebView`.
## `TealiumConfig`
### `WKProcessPool`
If you use a `WKWebView` webview in your app, create and retain a singleton `WKProcessPool` instance and set it prior to instantiating Tealium. This also prevents cookie synchronization issues if your app contains other webviews besides the Tealium Tag Management webview.
```obj-c
WKProcessPool *wkProcessPool = [[WKProcessPool alloc] init];
```
Example:
```obj-c
_configuration = [TEALConfiguration configurationWithAccount:@"ACCOUNT" profile:@"PROFILE" environment:@"ENV"];
_configuration.wkProcessPool = MyApp.wkProcessPool;
self.tealium = [Tealium newInstanceForKey:@"INSTANCE_KEY" configuration:_configuration];
```
### `WKWebviewConfiguration`
Permits a custom `WKWebviewConfiguration` object to be passed, which is used by the Tealium Tag Management webview. If using this option instead of `webviewProcessPool` option, set the singleton `WKProcessPool` through the customizable `WKWebviewConfiguration` `processPool` property.
It is recommended to use this option as it may be required if future API changes are made to `WKWebView`.
Example:
```obj-c
_configuration = [TEALConfiguration configurationWithAccount:@"ACCOUNT" profile:@"PROFILE" environment:@"ENV"];
WKWebviewConfiguration *webviewConfiguration = [[WKWebViewConfiguration alloc] init];
webviewConfiguration.processPool = MyApp.wkProcessPool;
_configuration.wkWebViewConfig = webviewConfiguration
self.tealium = [Tealium newInstanceForKey:@"INSTANCE_KEY" configuration:_configuration];
```